1. Field of the Invention
The invention relates to an inkjet head for use in an inkjet printer, and more particularly to techniques of achieving electrical continuity between remote contacts in the inkjet head.
2. Description of the Related Art
There are known inkjet heads for use in inkjet printers, which each incorporate a nozzle unit including a plurality of metal thin plates and a piezoelectric device. During a print operation of such a kind of inkjet head, drive signals are delivered to the piezoelectric device for ejecting ink droplets through nozzles contained in the nozzle unit, resulting in the formation of the desired image on a print medium.
More specifically, such a type of inkjet head is structured such that the piezoelectric device is affixed to a cavity unit comprised of the plurality of metal thin plates. In the thus-structured inkjet head, the nozzle unit and a support to which the nozzle unit is attached are each electrically held at a reference potential (e.g., a ground or earth potential).
The failure to electrically hold these nozzle unit and support at the reference potential invites an event of charging ink within the nozzle unit. If the ink is charged, then the piezoelectric device is chemically attacked (chemical erosion and corrosion occur in the piezoelectric device) due to the action of ionic compound in the ink, or the like. This creates the fear that the piezoelectric device will be deteriorated in quality in a shortened time of use.
For these reasons, a conventional inkjet head of such a type is used such that the cavity unit to which the piezoelectric device has been attached is grounded using silver paste. However, this constitutes one of factors causing an increase in cost.
It is known to use a coil spring as a part of electrical wiring, as disclosed in Japanese Patent Application Publications No. Sho 63-281877 and No. Hei 4-260398, for example.
More specifically, the above Publication No. Sho 63-281877 discloses an inkjet print apparatus in which a coil spring provides electrical continuity between a grounding member electrically connected with a metal component contained in a head unit (nozzle unit), and a metal base frame, and also protection of ink delivery tubing extending from an ink tank to the head unit containing the metal component.